1. Field of the Invention
The invention relates to ridge and mesa optical waveguides, and methods of making ridge and mesa optical waveguides.
2. Related Art
This section is intended to present to the reader various introductory concepts that may be related to various aspects of the present invention. As such, it is believed that this section may be helpful in providing the reader with information to facilitate a better understanding of the various aspects of the present invention. The statements of this section are to be read in this light and are not to be understood as admissions of prior art.
Ridge and mesa optical waveguides are well-known classes of multi-layer structures that are useful for guiding light along a selected pathway. Ridge and mesa optical waveguides can also be, as an example, optically integrated with active and passive electronic devices such as phase modulators and optical switches, configured for controlling and otherwise affecting the path and nature of light propagating through such optical waveguides. Optical waveguides, including ridge and mesa optical waveguides, typically include a core region surrounded by a cladding region. The core region has a higher refractive index than does the cladding region. The resulting refractive index gradient serves to confine a portion of the light to propagation through the core region. The ridge in a ridge optical waveguide additionally serves to optically channel light propagating at the top surface of a substrate located adjacent to the ridge, along a path defined by the lateral position of the ridge on the substrate. In an example, the ridge in a ridge optical waveguide may include portions of the core and cladding regions of the optical waveguide. The ridge may cause light to propagate in the substrate along the path of the ridge on the substrate. The ridge in a ridge optical waveguide may as an example define a path for a portion of an optical circuit. At the same time, wider lateral dimensions of the substrate relative to lateral dimensions of the ridge permits transmission of a greater optical bandwidth, through the substrate along a path in the same direction taken by light propagating through the ridge itself. In a mesa optical waveguide, the entire core and cladding regions may define a substantially integrated optical path.
There is a continuing need for new types of ridge and mesa optical waveguides, and for methods of making such ridge and mesa optical waveguides.